Citric acid, Fruit Fresh, lemon juice, crushed Vit. C tabs, etc. all work for color preservation. I get the best results with Fruit Fresh mixed per the label.

I've never tried drying green beans. When we don't have time to can them we freeze them. Easy and fast and good quality.

Peppers dehydrate ok if cut into small pieces but you end up with small bits of pepper. They too freeze so easily that is what we do when they get ahead of us.

Check out all the how-to dehydrate info at NCHFP for detailed instructions.

Dave

Here is a link that might be useful: NCHFP - Dehydrating Foods

We grow these often, and there are a couple of pounds of them in the fridge. I steam blanch them about 6 minutes -- two minutes longer than regular green beans, and then freeze them. If I were drying them, I would definitely blanch them first. This year we have a green variety, but I like the reds best because they hold their color after blanching.

To eat 'em up fresh, I've been playing with Indian spice blends like garam marsala in veggie stews heavy with yard long beans.